How do I seal drafty windows and doors before winter in Texas?
The first cold front of the season finds the weak spots in a Texas house fast. One room feels cold near the front door, another feels cold beside a bedroom window, and the heater runs longer to make up for air slipping out through the gaps. Sealing those gaps is a weekend job with cheap materials, and in Texas it pays off twice: it keeps warm air in during a cold snap and cooled air in during the long summer that follows.
Find the drafts before you buy anything
Start on a windy day, when moving air is easiest to trace. Hold a lit incense stick near the edges of each exterior door and window frame and watch the smoke. Smoke that drifts sideways marks a leak. For doors, add the dollar bill test: close the door on a bill and pull gently. A bill that slides out with little resistance means the seal at that spot has failed. Repeat the test at the top, both sides, and the bottom, since a door can seal on three sides and leak badly on the fourth.
Look for daylight around a closed door as well, and run a hand along the frame on a cold morning. Note which doors and windows leak and where, because the fix depends on the location. A gap between the frame and the wall needs a different product than a gap between a sash and its frame, and buying one tube of caulk for every leak will leave half of them unsealed.
Caulk the fixed gaps, weatherstrip the moving parts
The rule for choosing a product is simple. If the two surfaces stay still relative to each other, seal the joint with caulk. Scrape out old, cracked caulk first, then lay a steady bead along the seam where the frame meets the wall, on the outside of the house where the weather hits it. Smooth the bead and let it cure for the time stated on the tube before painting over it.
If the two surfaces move against each other, use weatherstripping. Clean the surface and let it dry before sticking adhesive foam or V-strip in place, since dust and dampness are the usual reasons adhesive strips peel off within weeks. Press the strip firmly along the full length of the gap, then close the door or window and check that it still latches without force. A strip that is too thick creates a new problem: a door that will not close properly will be left ajar, which leaks more air than the old worn seal did.
The gap under the door is the leak most people skip
Homeowners seal the sides of a door and wonder why the room still feels cold. The gap under the door is easy to miss because it sits below eye level, and it runs the full width of the doorway. A door sweep, screwed or stuck to the bottom of the door, closes that gap and brushes the threshold as the door swings. Check it after installation by looking for light under the closed door and by repeating the dollar bill test at the bottom edge.
For windows that will not be opened until spring, a clear window insulation film kit adds a second layer over a single-pane window. It is a seasonal fix rather than a permanent one, and it works best on the windows in the coldest rooms rather than on every window in the house. Our guide on when to turn on the heat in Texas covers the same timing question from the heating side: seal the drafts first, then let the heater run against a tighter house.
Why sealing drafts matters more in a Texas house
Texas winters are short, but they are sharp. A house in Dallas-Fort Worth faces its average first freeze around November 22, and a single hard freeze can expose every leaky door and window in one night. Sealing in late October gets the work done before that date, while the weather is still mild enough for caulk to cure properly. Our Dallas-Fort Worth first freeze checklist puts draft sealing alongside faucet covers and the backflow preventer cover, because all three are jobs that are much harder to do well once a freeze is already in the forecast.
The summer case is just as strong. A gap that leaks in January leaks in July, when the air conditioner is doing the heavy work. That is why a Texas homeowner should not treat draft sealing as a job that only matters for a few cold weeks. The same weatherstripping that stops a January draft stops cooled air from escaping in August, and it keeps dust and humid outdoor air out of the house in between.
Do not seal off the air a gas appliance needs
Sealing a house tighter is good for comfort and bills, with one safety limit. Gas furnaces, water heaters, and fireplaces that draw combustion air from inside the house need that air supply to work safely. Do not caulk or weatherstrip a vent, a flue opening, or the combustion air intake for one of those appliances, and do not seal a room containing one so tightly that it is starved of air. If a home has a gas appliance in a small utility closet, leave its venting alone and ask a heating technician about the air supply before sealing the closet door.
Rotted wood, a warped frame, or water staining around a window means the problem is bigger than a gap. Sealing over rot hides damage that keeps spreading underneath. In that case, get the frame repaired or replaced first, then seal the new work. The same applies to a door that will not latch even with new weatherstripping: the hinges or the strike plate may need adjustment, and forcing a thicker seal onto a misaligned door only wears the seal out faster.
Write it down while it’s fresh
In the Homwarden app, record the date the weatherstripping was replaced and set a reminder to recheck it next fall, alongside the other freeze prep jobs from the Dallas-Fort Worth outdoor faucet guide. A seal that is checked once a year stays a seal. A seal that is fitted and forgotten quietly stops working, and the draft comes back without anyone noticing the date it failed.
- Draft locations found with the incense test and the dollar bill test, noted door by door and window by window
- Caulk used on fixed frame-to-wall seams, weatherstripping used on moving sashes and door edges, and a sweep fitted under each exterior door
- A recheck each fall before the first freeze, since weatherstripping compresses and caulk cracks over a year of Texas heat
- Frame condition checked before sealing, with rot, warping, or water staining sent for repair instead of being sealed over
This is the part almost everyone skips, and it’s the part that pays. The next time this happens — or when a warranty claim, an insurance adjuster, or a buyer’s inspector asks — the answer is already written down. That is what homwarden is built to hold: maintenance, appliances, warranties, receipts, and records, filed with the equipment they belong to.
Common questions
How do I find a draft around a window or door?
On a windy day, hold a lit incense stick or a smoke pen near the frame and watch whether the smoke moves sideways. For a door, close it on a dollar bill and try to pull the bill out. If it slides out easily, the seal at that spot is weak. Check the top, the sides, and the bottom of each door, since one side can seal well while another leaks.
Should I use caulk or weatherstripping on a drafty window?
Use caulk on parts that do not move, such as the seam where the window frame meets the wall. Use weatherstripping on parts that move, such as the sash that slides or swings. Caulking a moving sash shut will stop the window from opening, and weatherstripping a fixed seam will not fill the gap well.
What is the best weatherstripping for an exterior door in Texas?
Foam tape is the cheapest and easiest option for a door with a fairly even gap, while V-strip (tension seal) holds up better on a door that gets heavy daily use. Rubber or vinyl bulb seals work well where the gap is uneven. Measure the gap first, because weatherstripping that is too thick will keep the door from latching.
Does sealing drafts help a Texas home in summer too?
Yes. The same gaps that let cold air in during a January cold snap let cooled air out during a Texas summer, when air conditioning runs for months. Sealing a leaky door or window frame is a year-round fix in Texas, not a winter-only job.
When should I call a professional instead of sealing a draft myself?
Call a professional when the frame is rotted or warped, the door will not latch after new weatherstripping, water is coming in around the frame, or the draft persists after the visible gaps are sealed. A persistent draft can point to missing insulation or a larger air leak behind the trim, which needs a different repair.
General maintenance guidance only. It is not a substitute for an inspection, a licensed contractor, an engineer, your insurer, the manufacturer’s instructions, or local code. When the stakes are gas, fire, structure, or standing water near electricity, stop and call a professional.